US Olympian Jessie Diggins, who's competing at the Winter Olympics, spoke to INSIDER about the sport.

"It's really aggressive because, unlike track or swimming, you don't have to stay in your own lane," she said.

For an average person, cross-country skiing is a pleasant way to spend a winter afternoon. For an Olympian, cross-country skiing is a punishing test of strength and endurance.

But American skier Jessie Diggins — who's currently competing in Pyeongchang 2018 — promises that it's fun, too.See the rest of the story at Business InsiderNOW WATCH: What abandoned Olympic venues from around the world look like todaySee Also:People are convinced figure skaters Tessa Virtue and Scott Moir are dating here's the truth behind their relationshipChloe Kim finally got to eat all the food she's been tweeting about at the Olympics and it was adorableThese two fan-favorite Olympians got matching tattoos after they failed to make the 2014 Olympics team